Improvement in elevators



UNITED STATES PATENT ()FFIG'E.

MARTIN L. WYMAN, OF BOSTON, MASSACHUSETTS.

IMPR'QVEMENT IN ELEVATORS.

Specification forming part of Letters Patent No. 156,835, dated November 10, 1874; application filed Ju y 16, 1874.

To all whom it may concern:

Be it known that I, MARTIN L. WYMAN, of Boston, in the county of Sufiolk and State of Massachusetts, have invented an Improve ment in Elevators; and I do hereby declare that the following, taken in connection with the drawings which accompany and form part of this specification, is a description of my invention sufficient to enable those skilled in the art to practice it.

The invention relates to means for automatically controlling thedescent of the car. 111 my invention I fix upon the winding-drum shaft, or any intermediate shaft, a wheel having peripheral recesses or pockets containing balls, said wheel being encompassed by a loose solid ring having a brake-band applied to it, the inner surface of this ring having recesses into which someone of the balls will be thrown by centrifugal force if the car in descending attains so rapid motion as to rotate the winding-drum with sufficient velocity to project the balls outward. The recess in the brake-ring is made so shallow as to only partially contain the ball thrown into it, and the ball, being thus lodged between the two wheels, causes the brake-ring to be moved with the wheel, and the motion of the drum and the car are thereby impeded to whatever extent friction is applied to the brake-rin My invention consists in the construction thus generally described.

The drawing represents a construction embodying my invention.

Figure 1 shows the parts in elevation. Fig. 2 is a plan of the same. Fig. 3 shows the ballcarrying wheel in elevation. Fig. 4 is a similar view of the brake-ring.

th e hoisting rope. 'rotates in suitable bearings, and has fixed upa denotes the winding-drum; b, the car; 0, The winding-drum shaft on its outer end the wheel (I. This wheel (I is encompassed peripherally by the annular wheel or ring 0, which turns loosely upon the wheel 61, and has extending around it, or partially around it, a brake-band, f, which may beheld automatically against the wheel 6 (and with sufficient force to control the descent of the car) by a Weighted lever, g. Thefast wheel (1 has in its periphery recesses or pocket-s h, each containing a ball, 2', and in the inner surface of the brake-ring or wheel a shallow recess, 7c, is formed.

As the drum-shaft rotates at unsafe speed the balls will be thrown centrifugally against the inner surface of the ring, and when either reaches the ring-recess it will enter the same, and thereby lock the wheel and ring together so that they will rotate as one, the Wheel being thus subjected to the same frictional or brake pressure exerted on the ring by the brake-band. This pressure causes the car to diminish its speed until the rotation of the drum is arrested.

1 claim-- I The combination of the annular brake-ring c, with the wheel cl, .upon the main windingdrum shaft or intermediate shaft, the wheel 01 containing one or more pockets, h, and balls z, and the ring-blank having one or more recesses, is, all substantially as shown and described.

MARTIN L. WYMIAN. Witnesses:

M. W; FROTHINGHAM,

S. B. KIDDER. 

